Why is this an issue?

Conditional expressions which are always true or false can lead to dead code. Such code is always buggy and should never be used in production.

Noncompliant code example

a = false;
if (a) { // Noncompliant
  doSomething(); // never executed
}

if (!a || b) { // Noncompliant; "!a" is always "true", "b" is never evaluated
  doSomething();
} else {
  doSomethingElse(); // never executed
}

Exceptions

This rule will not raise an issue in either of these cases:

• When the condition is a single final boolean

final boolean debug = false;
//...
if (debug) {
  // Print something
}

• When the condition is literally true or false.

if (true) {
  // do something
}

In these cases it is obvious the code is as intended.

Resources

• MITRE, CWE-570 - Expression is Always False
• MITRE, CWE-571 - Expression is Always True
• CERT, MSC12-C. - Detect and remove code that has no effect or is never executed